Add rule for multiline switch cases (#691)

nicklockwood · Aug 14, 2020 · 4027942 · 4027942
1 parent 587bacb
commit 4027942
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Showing 4 changed files with 59 additions and 3 deletions.
diff --git a/Rules.md b/Rules.md
@@ -21,6 +21,7 @@
 * [linebreaks](#linebreaks)
 * [modifierOrder](#modifierOrder)
 * [multilineEnumCases](#multilineEnumCases)
+* [multilineSwitchCases](#multilineSwitchCases)
 * [numberFormatting](#numberFormatting)
 * [preferKeyPath](#preferKeyPath)
 * [ranges *(deprecated)*](#ranges)
@@ -615,6 +616,10 @@ Option | Description
 
 Writes one enum case per line.
 
+## multilineSwitchCases
+
+Writes one switch case per line.
+
 ## numberFormatting
 
 Use consistent grouping for numeric literals. Groups will be separated by `_`

diff --git a/Sources/Rules.swift b/Sources/Rules.swift
@@ -3471,6 +3471,29 @@ public struct _FormatRules {
         }
     }
 
+    /// Writes one switch case per line
+    public let multilineSwitchCases = FormatRule(
+        help: "Writes one switch case per line.",
+        options: [],
+        sharedOptions: ["linebreaks", "tabwidth", "indent", "smarttabs"]
+    ) { formatter in
+        formatter.forEach(.endOfScope("case")) { idx, _ in
+            guard let colonIndex = formatter.index(of: .startOfScope(":"), after: idx) else { return }
+
+            var startIndex = idx
+            while let delimiterIndex = formatter.index(of: .delimiter(","), after: startIndex),
+                let nextCaseIndex = formatter.index(of: .operator(".", .prefix), after: delimiterIndex)
+            {
+                if formatter.index(of: .linebreak, in: delimiterIndex ..< nextCaseIndex) == nil {
+                    formatter.insertLinebreak(at: delimiterIndex + 1)
+                    formatter.insertSpace(formatter.spaceEquivalentToWidth(5), at: delimiterIndex + 2)
+                }
+
+                startIndex = nextCaseIndex
+            }
+        }
+    }
+
     /// Normalize the use of void in closure arguments and return values
     public let void = FormatRule(
         help: "Use `Void` for type declarations and `()` for values.",
@@ -3571,7 +3594,6 @@ public struct _FormatRules {
             // TODO: other cases
         }
     }
-
     /// Standardize formatting of numeric literals
     public let numberFormatting = FormatRule(
         help: """

diff --git a/Tests/RulesTests.swift b/Tests/RulesTests.swift
@@ -4708,6 +4708,30 @@ class RulesTests: XCTestCase {
         testFormatting(for: input, output, rule: FormatRules.multilineEnumCases)
     }
 
+    // MARK: multilineSwitchCases
+
+    func testMultilineSwitchCases() {
+        let input = """
+        switch enum1 {
+        case .a(_), .b, .c:
+            print("")
+        case .d:
+            print("")
+        }
+        """
+        let output = """
+        switch enum1 {
+        case .a(_),
+             .b,
+             .c:
+            print("")
+        case .d:
+            print("")
+        }
+        """
+        testFormatting(for: input, output, rule: FormatRules.multilineSwitchCases)
+    }
+
     // MARK: - void
 
     func testEmptyParensReturnValueConvertedToVoid() {
@@ -8384,7 +8408,7 @@ class RulesTests: XCTestCase {
     func testHoistCommaSeparatedSwitchCaseLets() {
         let input = "switch foo {\ncase .foo(let bar), .bar(let bar):\n}"
         let output = "switch foo {\ncase let .foo(bar), let .bar(bar):\n}"
-        testFormatting(for: input, output, rule: FormatRules.hoistPatternLet)
+        testFormatting(for: input, output, rule: FormatRules.hoistPatternLet, exclude: ["multilineSwitchCases"])
     }
 
     func testHoistCatchLet() {
@@ -8507,7 +8531,11 @@ class RulesTests: XCTestCase {
         let input = "switch foo {\ncase let .foo(bar), let .bar(bar):\n}"
         let output = "switch foo {\ncase .foo(let bar), .bar(let bar):\n}"
         let options = FormatOptions(hoistPatternLet: false)
-        testFormatting(for: input, output, rule: FormatRules.hoistPatternLet, options: options)
+        testFormatting(for: input,
+                       output,
+                       rule: FormatRules.hoistPatternLet,
+                       options: options,
+                       exclude: ["multilineSwitchCases"])
     }
 
     func testUnhoistCommaSeparatedSwitchCaseLets2() {

diff --git a/Tests/XCTestManifests.swift b/Tests/XCTestManifests.swift
@@ -919,6 +919,7 @@ extension RulesTests {
         ("testMultilineInitBraceOnNextLine", testMultilineInitBraceOnNextLine),
         ("testMultilineMapPropertyToKeyPath", testMultilineMapPropertyToKeyPath),
         ("testMultilineStringWithEscapedLinebreak", testMultilineStringWithEscapedLinebreak),
+        ("testMultilineSwitchCases", testMultilineSwitchCases),
         ("testMultipleAttributesNotSeparated", testMultipleAttributesNotSeparated),
         ("testMultipleClosureArgumentUnwrapped", testMultipleClosureArgumentUnwrapped),
         ("testMultipleNestedClosures", testMultipleNestedClosures),